Five-strong East Anglian diy store chain Coopers has switched to seven day trading.
The outlets in Great Yarmouth, Beccles, Halesworth, Bungay and Leiston started opening on Sundays in June.
The move came to meet customer demand. "They'd been asking us to open on Sundays," managing director Phil Tate told DIY Week. "They said that, if they were shopping on a Sunday, then - especially customers at our market town stores - they'd have to go to the B&Qs in larger towns such as Norwich and Lowestoft.
He added: "Now they're telling us that we've saved them a trip."